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Contaminants in Groundwater near North Penn Area Superfund Sites

USGS has investigated groundwater flow and contaminant transport in the vicinity of Superfund sites in Montgomery County, southeastern Pennsylvania, in cooperation with EPA. Additional cooperative support for these investigations has been provided by the Pennsylvania Department of Environmental Protection, Montgomery County, and local government agencies.

Highlights

Industrial solvent contaminants have migrated in fractured-rock aquifers in the vicinity of North Penn Area Superfund sites

Newark Basin aquifers of the Brunswick Group and the Lockatong Formation have been used for industrial and drinking-water supply

Field testing characterized the highly heterogeneous and anisotropic strata showing the predominant role of bed-oriented fractures in contaminant migration

Measured water levels in wells were used to construct water-level maps, and aquifer testing revealed high-permeability hydraulic connections between wells

Groundwater-flow models were developed based on synthesis of field-test results using a 3D hydrogeologic framework of dipping mudstone and shale strata

Simulations of transport paths were compared to observed contaminant distributions, and the simulated effect of changes in pumping on flow paths helped optimize pump and treat system operation

Areas contributing recharge to streams and discharging wells were mapped using the groundwater-flow models; as groundwater withdrawals in the area have decreased, a higher proportion of local recharge ultimately discharges to streams

Reports, Articles, Maps, and Presentations

Effects of Changes in Pumping on Regional Groundwater-Flow Paths, 2005 and 2010, and Areas Contributing Recharge to Discharging Wells, 1990-2010, in the Vicinity of North Penn Area 7 Superfund Site, Montgomery County, Pennsylvania: USGS Scientific Investigations Report 2017-5014

Geophysical Logs, Aquifer Tests, and Water Levels in Wells in and Near the North Penn Area 7 Superfund Site, Upper Gwynedd Township, Montgomery County, Pennsylvania, 2002-2006: USGS Report SIR 2008-5154

Borehole Geophysical Logging and Aquifer-Isolation Tests conducted in well MG-1693 at North Penn Area 5 Superfund Site near Colmar, Montgomery County, Pennsylvania: USGS Report SIR 2006-5014

Interpretation of Geophysical Logs, Aquifer Tests, and Water Levels in Wells in and near the North Penn Area 7 Superfund site, Upper Gwynedd Township, Montgomery County, Pennsylvania, 2000-02: USGS Report SIR 2005-5069

Altitude and Configuration of the Water-Level Surface in Mesozoic Sedimentary Rocks at and Near the North Penn Area 7 Superfund Site, Upper Gwynedd Township, Montgomery County, Pennsylvania, December 4-6, 2000: USGS Report OFR 2004-1006

Simulation of Aquifer Tests and Ground-Water Flow Paths in fractured shales and sandstones of the Brunswick Group and Lockatong Formation, Lansdale, Montgomery County, Pennsylvania: USGS Report OFR 00-97

Altitude and configuration of the Potentiometric Surface in Lansdale and vicinity, Montgomery County, Pennsylvania, August 22-23, 1996: USGS Report OFR 98-253

Evaluation of Hydrologic Data collected at the North Penn Area 12 Superfund Site, Montgomery County, Pennsylvania: USGS Report WRIR 98-4076

Altitude and configuration of the Potentiometric Surface in the Upper Triassic sedimentary rocks at and near the North Penn Area 12 Superfund site, Worcester Township, Montgomery County, Pennsylvania, July 20-27, 1995: USGS Report OFR 95-747